Whilst working for a client with a large Oracle estate, supporting high transaction systems, we found that the in-built auto-extend feature, designed to increase the size of the tablespaces automatically was actually making Operational Capacity Management harder.
Given nothing but the size of the database it was difficult to apportion the amount of growth due to real business demand and how much was just auto-extend kicking in. This made it harder to accurately predict the amount of life left in the system, the critical question we were trying to answer in order to ensure service continuity.
In databases exhibiting high storage utilisation auto-extend was even more dangerous as there was a strong likelihood of it trying to claim a larger block of space than was needed or available and bringing down the system as a result.
The solution in this scenario? Just switch it off for highly utilised databases.
It makes me wonder what other foes might be lurking out there with friendly capacity management masks on…
